Voice-operated gas lamp stroboscopes

ABSTRACT

Apparatus for producing light flashes responsive to vocal sound vibrations having a flashing rate related to the vocal sound frequencies, for use by physicians as a light source for light to be reflected into a patient&#39;&#39;s throat for observation by the physician of the behavior and condition of the vocal chords. The apparatus is in the form of a voice-operated stroboscope comprising a normally nonconductive trigger vacuum tube which is controlled by an audio frequency amplifier coupled to an acoustic transducer activated responsive to vocal sounds produced by the patent. The trigger vacuum tube is connected to a stroboscopic lamp to produce light flashes approximately synchronized with the audible vibrations of the patient&#39;&#39;s vocal chords.

Waited States atent [1 1 Meyers Sept. 24, 1974 VOlCE-OPERATED GAS LAMP [73] Assignee: Madison College Foundation, Inc., Harrisonburg, Va. a part interest [22] Filed: Aug. 27, 1973 [21] Appl. No.: 391,848

Related US. Application Data [63] Continuation of Ser. No. 191,240, Oct. 21, 1971,

Miura et al. 128/2 R Gunn et al. 128/2 R Primary ExaminerLucie H. Laudenslager Attorney, Agent, or Firm-Mason, Fenwick & Lawrence [5 7 ABSTRACT Apparatus for producing light flashes responsive to vocal sound vibrations having a flashing rate related to the vocal sound frequencies, for use by physicians as a light source for light to be reflected into a patients throat for observation by the physician of the behavior and condition of the vocal chords. The apparatus is in the form of a voice-operated stroboscope comprising a normally nonconductive trigger vacuum tube which is controlled by an audio frequency amplifier coupled to an acoustic transducer activated responsive to vocal sounds produced by the patent. The trigger vacuum tube is connected to a stroboscopic lamp to produce light flashes approximately synchronized with the audible vibrations of the patients vocal chords.

3 Claims, 11 Drawing Figure VOICE-OPERATED GAS LAMP STROBOSCOPES This is a continuation of application Ser. No. 191,240, filed Oct. 21, 1971, now abandoned.

BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates to a diagnostic instrument useful in medicine, research and teaching the behavior and ailments of human vocal chords. It employs a combination of audio-frequency amplifier and a gaseous lamp.

This Gas-Lamp STROBOSCOPE is VOICE- OPERATED, and will enable a physician or any medical researcher to visualize human vocal chords stroboscopically during a patients vocalization of sounds. This invention represents a new and unique combination of a conventional audio-frequency amplifier and a trigger circuit to flash a conventional gaseous stroboscope lamp in precise step with the frequency of vibration of the human vocal chords, thereby enabling the observer to directly view and/or photograph the vocal chords as though their vibrations were motionless. Although the present state of the electronic art provides for satisfactory types of audio-frequency amplifiers and gaseous stroboscope lamps, nevertheless, the unique combination of a voice-operated amplifier and a gaseous stroboscopic lamp is the basis for this invention.

The ultimate benefit to be derived from the application of this invention resides in medical diagnosis and treatment of vocal chord ailments. The human larynx may be afflicted with a variety of organic ailments. Among them, chronic hoarseness; malignant growths; vocal chord paralysis associated with psychological problems; professional artists voice ailments among singers and public speakers, who have vocal ailments. These may readily be examined and diagnosed, either by direct stop-motion stroboscopic visualization by reflection of the light from the stroboscopic lamp via the physician-observers conventional head mirror and usual hand-held examining mirror into the patients throat to the vocal chord region and reflecting the vocal chord image back via the examining mirror and through the hole in the head mirror to the physicians eye. Alternatively or additionally, color motion picture photographs may be taken via reflection of the vocal chord image from an auxiliary mirror that is attached to the observers head-mirror.

DETAILED DESCRIPTION OF EMBODIMENT I hereby declare the following to be a full, clear, and exact description of this invention, such as will enable others skilled in the art to which it pertains, to make, use, and sell the same, reference being had to the accompanying schematic drawing, which forms part of this specification. It is further declared that other electrical, and/or mechanical configurations are contemplated, such as variations in the arrangement, combination, and choice of the several components; like: vacuum tubes; transistors; diodes; gaseous stroboscope lamps which may be operated at sonic, as well as at subsonic or super-sonic frequencies; without departing from the spirit of this invention.

My invention relates to a VOICE-OPERATED GAS- LAMP STROBOSCOPE, which enables an observer to view and/or photograph the blurred motion resulting from vibrations of the vocal chords as though they were motionless; by employing an amplified input voice signal to trigger the flashes of light from a gaseous stroboscope lamp in sympathetic response to the incident vocal stimulus.

Reference to the schematic circuit diagram shows:

A combination of two sections, namely: the microphonedriven transistorized audio-frequency amplifier coupled to its biasing triggering triode; and the highvoltage thermionically-rectified power supply connected in series with the stroboscopic gas-filled lamp and the triggering triode vacuum tube.

The dynamic operation of the Voice-Operated Stroboscopic Gas Lamp occurs when the incident voicesignal activates the dynamic microphone M1, or a similar acoustic transducer; whose output voltages are stepped-up three-fold by the audio-frequency transformer T1. The output signals are controlled by the volume control R1 (also indicated as V.C.); and are then amplified by the P.N.P. type transistor TRl through the coupling capacitor C1 and the voltage divider network R2, R3, and C8. The transistor TRI is biased in the emitter circuit by resistor R, which is shunted by the capacitor C to prevent amplifier degeneration. Output voltage signals are developed across the load resistor R5 in the collector circuit of transistor TRl. The preamplified audio-frequency signals are then resistancecapacity coupled to the base of the driver transistor TR2 through the coupling capacitor C3 and the voltage divider R6, R7. Bias voltage is provided for transistor TR2 by means of the emitterconnected resistor R8 and its shunt-connected capacitor C4. The collector of transistor TR2 delivers an amplified signal voltage of sufiicient magnitude to the primary coil of the input transformer T2, the secondary of which is connected to the push-pull audio-frequency amplifier transistors TR3; TR4 by means of the center-tapped secondary coil. The emitters of the push-pull amplifier transistors TR3; TR4 are biased by resistors R10; R11. To prevent thermal runaway because of the negative-resistance property of a transistor, a thermistor TI-I is shunted across a bias resistor R10 which compensates for these resistance-temperature changes in the push-pull transistorized amplifier circuit. The collectors of the pushpull transistors TR3, TR4 deliver their amplified signals to the primary coil of the push-pull output transformer T3 which is shunted by the capacitor C5. The highimpedance secondary coil of the transformer T3 delivers a triggering voltage to the control grid of the trigger tiode vacuum tube V1 whose function is to fire the gaseous stroboscope lamp G.L. in synchronism with the incident audio-frequency vibrations. The stroboscope gas lamp is connected in series with the trigger triode vacuum tube V1 and with the high-voltage power supply which is obtained from the half-wave vacuum tube diode rectifier V and its pi-ripple filter C6, R13, C7 which follows the secondary coils of the power transformer T4. The primary coil of the power transformer T4 is connected to the ll5-volt AC power line by means of a male plug Pl, an on-off line switch S1, a fuse F1, and a neon indicator pilot lamp Ne.

The filaments of the diode rectifier tube V2 and the triode trigger vacuum tube V1 are respectively heated by their separate low-voltage secondary coils provided by the power transformer T4. The transistorized audiofrequency amplifier derives its required DC voltages from the 9-volt battery B which is connected to the ground and to the voltage-dropping resistor R9. Voltage is fed to the collectors of the respective P.N.P.-type transistors of the audio-frequency amplifier. The volume control (R1, V.C.) is used to pre-adjust the audio signal level to the critical value necessary to fire the trigger tube in response to the amplitude level of the voice under visual observation.

The following are representative values of the circuit elements of the embodiment shown in the accompanying drawing:

Rl -5K Cl 10 mfd; lOv. R2 4K C2 30 mfd; 6 v. R3 39K C3 -10 mfd; 10 v. R4 l.2 K C4 5O mfd; l v. R K C5 .02 mfd; l0 v. R6 6.8 K C6 l mfd; 1000 v. R7 K C7 l mfd; 1000 v. R8 330 ohms.

R9 220 ohms.

R10 330 ohms.

Rll 1 ohm.

R13 l0 K The foregoing combination and arrangement of these hybrid components comprising transistors; vacuum tubes; and a gas lamp delivers an amplified voice signal of sufficient magnitude to trigger the gas-lamp stroboscope in synchronism with the incident audio frequency vibration.

Since there is a short time-lag between the origin of the sound vibration and its subsequent arrival at the microphone, the observed light caused by the original sound will experience a brief time-delay. The endresult enables the observer to see a nearly-motionless view of the rapidly-moving vocal chords which are the source of the vibrations that originated slightly earlier than the delayed visual flashes of the gas-lamp. The observer is thereby enabled to dynamically view the rapidly-moving vocal chords in slow motion for diagnosis of ailing vocal chords which are now under physical strain; as opposed to their appearance to the observer when the vocal chords are not strained because they are at rest.

In using the voice-operated stroboscope to examine the patients vocal chords, the usual physicians apertured concave head mirror and hand-held inclined examining mirror are employed in the usual manner, with the hand-held examining mirror inserted through the patients mouth and directed to permit observation of the vocal chord region and the conventional apertured physicians head mirror positioned to direct light into the patients mouth to be reflected by the inclined head-held examining mirror to the vocal chord region. By employing the stroboscopic gas lamp G.L. of the present invention as the light source for the physicians head mirror, instead of the usual incandescent lamp, and thereby reflecting the flashes from the gas lamp into the patients mouth, the physician-observer is able to see a nearly-motionless view of the rapidly-moving vocal chords producing the sounds which activate the microphone which is positioned to pick up the incident voice signals.

The ultimate advantage to be derived from this invention lies in its provision for pre-treatment observation and/or photography of the affected vocal chords followed by subsequent observation and/or photography after medical and/or surgical treatment. A related advantage of this invention is in its application to teaching to groups in clinics and medical schools by employing a closed-circuit television camera at the site of the motion picture camera.

What is claimed is:

l. A voiceoperated stroboscope, comprising an acoustic transducer microphone to be supported near the mouth of a patient to be actuated by sound pressure variations caused by the larynx of the patient when producing selected sounds, an audio-frequency amplifier having an input coupled to said transducer and an output having means providing trigger voltages for activating a trigger tube to conduct in predetermined time-lag and phase relationship to vibrations produced by the patients vocal chords, a normally non-conductive electrical current control trigger tube having a control grid coupled to the output of said amplifier to be triggered into a state of conduction responsive to amplified signals representing vibrations of the vocal cords, said time-lag and phase relationship being determined by the amplitude of the amplified signals applied to said trigger tube relative to its threshold trigger voltage and by the distance from the transducer microphone to the vocal chords, and a gaseous stroboscopic lamp having an anode coupled to said current control trigger tube to produce light flashes upon conduction of the latter to enable incident sounds from the vocal chords of the patient to trigger the flashes of the stroboscopic lamp substantially in synchronism with the individual audible vibrations of the patients vocal chords so that an observer may view or photograph such dynamic motion as though the vocal chords were nearly motionless.

2. A voice-operated stroboscope as defined in claim ll, wherein said audio-frequency amplifier in a multistage amplifier and includes a first transistor amplifier stage having its input coupled by an audio-frequency transformer to said transducer microphone, a driver transistor amplifier stage coupled to the output of said first amplifier stage, and a pair of transistors forms a push-pull audio-amplifier stage coupled to the output of said driver amplifier and providing the trigger voltages for firing said stroboscopic lamp in predetermined phase relation to the sound-responsive signals produced by the transducer microphone.

3. A voice operated stroboscope as defined in claim 2, having a direct-current power supply coupled to an element of the stroboscopic lamp. 

1. A voice-operated stroboscope, comprising an acoustic transducer microphone to be supported near the mouth of a patient to be actuated by sound pressure variations caused by the larynx of the patient when producing selected sounds, an audio-frequency amplifier having an input coupled to said transducer and an output having means providinG trigger voltages for activating a trigger tube to conduct in predetermined time-lag and phase relationship to vibrations produced by the patient''s vocal chords, a normally non-conductive electrical current control trigger tube having a control grid coupled to the output of said amplifier to be triggered into a state of conduction responsive to amplified signals representing vibrations of the vocal cords, said time-lag and phase relationship being determined by the amplitude of the amplified signals applied to said trigger tube relative to its threshold trigger voltage and by the distance from the transducer microphone to the vocal chords, and a gaseous stroboscopic lamp having an anode coupled to said current control trigger tube to produce light flashes upon conduction of the latter to enable incident sounds from the vocal chords of the patient to trigger the flashes of the stroboscopic lamp substantially in synchronism with the individual audible vibrations of the patient''s vocal chords so that an observer may view or photograph such dynamic motion as though the vocal chords were nearly motionless.
 2. A voice-operated stroboscope as defined in claim 1, wherein said audio-frequency amplifier in a multi-stage amplifier and includes a first transistor amplifier stage having its input coupled by an audio-frequency transformer to said transducer microphone, a driver transistor amplifier stage coupled to the output of said first amplifier stage, and a pair of transistors forms a push-pull audio-amplifier stage coupled to the output of said driver amplifier and providing the trigger voltages for firing said stroboscopic lamp in predetermined phase relation to the sound-responsive signals produced by the transducer microphone.
 3. A voice operated stroboscope as defined in claim 2, having a direct-current power supply coupled to an element of the stroboscopic lamp. 